The present invention relates to structures for suppressing pulsation in compressors in which gas flows from a suction chamber into a cylinder bore by reciprocation of a piston.
In general, a suction port and a discharge port are formed in a valve plate provided in a compressor. Opposed to the suction port and the discharge port, respectively, a suction valve and a discharge valve are provided so that they can be opened and closed. With reciprocation of a piston, gas is drawn through the suction port into the cylinder bore by forcing the suction valve to open. In this kind of compressor, the pressure in the suction chamber may vary periodically upon compression due to opening of the suction valve and vibration, and so-called suction pulsation may occur.
The larger the volume of the suction chamber in the compressor is, the more such suction pulsation is suppressed. Japanese Unexamined Patent Publication No. Hei 7-269462 discloses a compressor in which an auxiliary suction chamber is provided to expand the suction chamber. Such an expanded suction chamber further improves the suppression of suction pulsation.
To expand the suction chamber, the auxiliary suction chamber is provided on an extension of the axial line of a rotary shaft. Therefore, a space for the auxiliary suction chamber is required within the cylinder block. As a result, the length of the cylinder block increases, and the size of the compressor increases. In case of a compressor incorporated in a vehicle, an increase in size of the compressor may bring cause interference with parts of the vehicle other than the compressor, which is undesirable.
It is an object of the present invention to provide a compressor with improved pulsation suppression, however, the compressor is not enlarged.
In order to attain the above object, the present invention present invention provides a compressor as described below. That is, the compressor includes a housing having an opening portion and a cylinder block. A rotary shaft is supported by the housing. A plurality of cylinder bores are provided in the cylinder block around the axis of the rotary shaft. A discharge chamber and a suction chamber are formed in the housing. A valve plate separates each cylinder bore from the suction chamber and the discharge chamber. A plurality of discharge ports and a plurality of suction ports corresponding to the respective cylinder bores are formed in the valve plate. A piston accommodated in each cylinder bore compresses gas drawn into the cylinder bore through the corresponding suction port. The compressed gas is discharged from the cylinder bore into the discharge chamber through the corresponding discharge port. An introduction passage extends from the opening portion toward the suction chamber and then bends and further extends toward the valve plate. The introduction passage connects the opening portion of the housing with the suction chamber to allow gas to flow therethrough.